Bhagavad Gita 13.7इच्छा द्वेषः सुखं दुःखं सङ्घातश्चेतनाधृतिः।एतत्क्षेत्रं समासेन सविकारमुदाहृतम् ॥

These principles form the frame or the skelteton on which the world of forms is built. All these are mental states and treated as properties of the body by the Sankhya school of thought. According to the NyayaYaiseshika schools, these are the inherent alities of the Self. The modifications have a beginning and an end. Only that which is unchanging can be the witness of these modifications. The knower of the field is unchanging. He is the witness of the field and its modifications.Desire is a modification of the mind. It is an earnest longing for an object. It is a Vritti (thoughtwave) born of Rajas which urges a man who has once experienced a certain object of pleasure to get hold of it as conducive to his pleasure when he beholds the same object again. This is the property of the inner sense. It is the field because it is knowable.You enjoy a certain sensual object. The impression of this is produced in the subconscious mind. This impression is vivified or revived through memory or remembrance of the sensual pleasure. Then desire arises to enjoy the object again. Repetition of the sensual enjoyment intensifies the memory and desire. Renunciation of the objects and meditation thin out the impressions and the desires.If anyone gives a description of the beautiful scenery of Badri Narayana or Mount Kailasa at once a desire arises in our minds to vist those places